Supplex Libellus Valachorum Transsilvaniae (Latin for Petition of the Romanians of Transylvania) is the name of two petitions sent by the leaders of the ethnic Romanians of Transylvania to the Holy Roman Emperor Leopold II, demanding equal political rights with the other ethnicities of Transylvania and a share of the Transylvanian Diet proportional to their population.
The first Supplex was sent in March 1791 by Ignatie Darabant, the Greek Catholic bishop of Oradea, to the State Council of Vienna. The second Supplex, a largely expanded and argumented version of the first, was brought before the Imperial Court of Vienna on March 30, 1792, by Ioan Bob, Greek Catholic bishop of Blaj, and by Gherasim Adamovici, Orthodox bishop of Transylvania.
The demands in the petition, according to the researches of David Prodan, were largely based on the Declaration of the Rights of Man and of the Citizen of Revolutionary France, and it also included an essay reviewing historical reasons (such as references to a Roman Dacia-Romanian continuity) as well as statistics about the Romanians (who made up approximately 55% of the population of Transylvania). According to some more recent researches, the argumentation of the Supplex Libellus Valachorum based on the ideas of natural law as well as on the Hungarian feudal judicial argumentation.